Domolite lime and other lost arts...

[Dolf]

When I posted a reply on reefs.org and said they may wish to give dolomite a try it came with the warning that it is second hand knowledge. I do plan on adding a DSB in spring when I can get it (provided that the tank is still up- if I move North to a camp job I do not think they will let me take my reef on the little plane [img]images/smiles/icon_biggrin.gif[/img] ) Right now after the lighing upgrade and new pump I cannot afford the aragonite to put in the tank so one way or the other it will be spring before the main tank gets the DSB. (I need to wait for the dolomite to be in stock or for my "real" job to afford it.)

As for the magnesium I guess we will see. I asked Dr.Ron a question about the PH in the lower levels of the DSB and so far no response. I will provide the link at the end and will post his reply when received. This should help to either stir up debate about the Magnesium not being as soluble as we think or more soluble depending on what the answer is and who will wish to disagree.

From what I know (thanks to a response from a reefer who seems very knowledgeable on another board) it would take a PH of roughly 7.6 and a large amount of CO2 to pose a problem. I think that there is a lower number if it is not in the presence of CO2 but I will have to search. If the response from Dr.Ron comes back that the PH is 7.6 or lower then I may start questioning the use of dolomite. Above 7.6 and I would assume that there will be fewer arguments? (Or not)

here is the link and I only hope the good Dr. has an answer and that the research has been done.

-Danny

[ 24 January 2002: Message edited by: dan150 ]</p>

[DJ88]

Nice to see you here Dan..

Glad you are joining in. The more the merrier. [img]images/smiles/icon_smile.gif[/img]

I'll keep an eye out for Dr Ron's response.

By far this is one of the most enjoyable debates I have had in a while.

You agree Victor? [img]images/smiles/icon_biggrin.gif[/img]

[StirCrazy]

ok I am not sure about this so I am asking about it. with the lower regeon of a DSB there have been studies that have showen that it is lower PH than the water colum, now from the last 23 years of keeping planted fresh water tanks and trying out tones of different soiles ranging from kittly litter to laterdite, I have always had a4 to 6" bed in my freshwater tanks and although I think we get some of the same benifits in nitrate reduction as I get anerobic zones in my fresh tanks and no matter how much nitrate I add with my fertalizer I cannot get my nitrates in the tank above 0 ( I want it to stable out at 10ppm)
Now that I have explained the madness behind my thinking I am wondering if what is going on under the sand bed affects the water colume at all? why do I think this? well in freshwater tanks we add iron and phosfate ritch fretalizer sticks below the sand bed for root feeders. they desolve and feed the plants but I never have a high iron level or any phosfates in my water colume. now in a reef tank whare the PH is 8ish lets say the bottom of the sand bed is 7, in theory stuff that will desolve at 7.2 shold start desolving how fast do you have to replenish your sand bed? seeing that arganite desolves faster than dolomite it would take a lot longer for the same volume in dolomite to be desolved, which would in turn result in a slower rate of particles being released into the bottom area of the sand bed.
my theory is that as the elements are working there way throught the sand bed to towards the water colum, most will bond with other particles in the substrate and never make it to the water colum. in a sence the upper 3 to 4 " of the sandbed is acting like a filter causing most of the elements to precipatateout of solution befor it can reach the water colume. does this make sence? think about it,

if this wasn't happening you would never have to add kalk, run a calcium reactor or use stuff like ionic B. all you would have to do is keep replenishing your sand bed because at a ph of 7.5 I have showen that arganite will desolve untill it buffers to 7.8 ish in my exparament.

well I have more to say but I am going toleave this at that. this post doesent say which is better just gives some food for thought on what is actualy going on in a DSB. like I stated I have been running DSB and quasi DSB, for about 23 years now and this is something I have been thinking about for a long time, just with freshwater and not salt, but the mechanics are the same.

Please I want to hear your thought on this as it is just my theory and if you have evidence to prove it wrong then I stand to learn from it.

Steve

[reefburnaby]

Hi,

Yes, I agree that this is one of the most interesting debates we have had in a while. Thankfully, it was a mature debate...not a screaming match.

I don't think I want to pull out my domolite right now...just before the meeting [img]images/smiles/icon_biggrin.gif[/img] I'll give it a year or two and see what happens.

- Victor.

[powerreef]

hey boys are we having fun yet. Here is a couple of more tid bits for the debat.
This is an article from The Conscientious Reef Aquarist, it dealt with a number of sand bed issues but here is the one that dealt with types of substraigts

"Dolomites

(CaMg(CO3)2 are the least soluble source; they barely fizz when cold hydrochloric acid is test-dripped on them. Dolomite, as the poorest buffer, should only be selected for sparsely populated systems, and only for cost considerations. There has been speculation that it is possibly contaminated with toxic metals (Dewey 1984).

Calcites

(CaCO3, e.g. limestones, marbles are almost pure calcium carbonate; they are more soluble that the various sources/types of dolomites with their regular calcium and magnesium structure, but less soluble than...

Calcite with magnesium impurities.

Coral sand, crushed oyster and coral rock. These are the most suitable media and buffers.

Size (2-5mm), shape (spherical), grading (all the same), and circulation (2+ gsfm, the more the merrier) have been gone over under properties"


Hers another article from Aquarium Frontiers it talks about the needs for sand beds and types and also had this paragraph in it.

"One of the last but most overlooked advantages of a substrate is the ability for calcium and carbonate ions to be naturally released into the water by its dissolution. This natural process helps maintain high calcium and alkalinity levels, while reducing nitrates, phosphates, and iodates. Do not use Dolomite or Gypsum as they contain excess levels of magnesium and sulfate respectively. Dolomite may be used to help maintain magnesium levels in conjunction with a calcium reactor. Only use small amounts in conjunction with aragonite and closely monitor magnesium levels."


anyway thiers 2 more and I'm to tired to get more. you know this stuff is just gym chalk right

[DJ88]

Steve,

I am getting a few things together to answer your questions.. Just so you know.

Victor,

I would NOT want to change a sand bed jsut before a meeting. I have change substrate out before.. ick ick ick ick hee hee.

See ya saturday.

[Dolf]

The response to the PH question I asked has been answered by Randy Holmes-Farley where in part he said "In my tank, the sand bed has a pH in the mid to upper 7's. My sand is calcium carbonate (oolitic aragonite), which is dissolving at that the low end of that pH range. I'm quite sure that dolomite will also dissolve at that pH. But, the diffusion of magnesium up to the surface is going to be slow, and the magnesium level in seawater is more than 5 times the calcium (on a mole basis). Consequently, I don't see the dissolution of dolomite in deeper regions of the sand as being a big problem."

He also makes reference to a fellow named Spotte who did an extensive write-up in "captive seawater fishes." I would like to see if I can find this as it would probably answer a couple of questions that still remain.

For now I am still committed to adding Dolomite now more that ever just to study it and see the effects. If nothing else came out of this for myself I now know that I will be keeping a close eye on the magnesium levels and testing for it once a month. The link to the question and whole answer (well worth reading) is http://www.reefcentral.com/vbulletin...threadid=58766

-Danny

[Shadetree]

FYI, most of our dolomite comes from Washington where these results are from Check out LEAD, NICKEL, ARSENIC and some of the others.

PRODUCT: DOLOMITE

TOTAL METALS IN PRODUCT ppm

Arsenic <6.25
Cadmium <1.25
Cobalt <1.25
Mercury <0.1
Molybdenum <2.5
Nickel <1.25
Lead <6.25
Selenium <12.5
Zinc <3.75

And the other one,

PRODUCT: DOLOMITE

TOTAL METALS IN PRODUCT ppm

Arsenic <2.5
Cadmium 0.76
Cobalt 1.5
Mercury <0.0278
Molybdenum <1
Nickel 0.412
Lead 49
Selenium <2.5
Zinc 224

http://www.wa.gov/agr/

Scott

[ 26 February 2002: Message edited by: Shadetree ]</p>

[StirCrazy]

I personaly have decided to go with sugar sand as I did a month long test on about one pound of each substrate and I wan't totaly happy with the amount the lime compacted. it might be harmless but it was a little to hard for my liking. having said that this is the sheet for mighty white dolomite.. I am not sure what brand you posted Shadetree, maby generic?

PRODUCT: MIGHTY WHITE DOLOMITE LIME

GUARANTEED ANALYSIS (%)
TOTAL METALS IN PRODUCT (ppm)

Arsenic <2.5
Cadmium 0.3
Cobalt 0.5
Mercury 0.005
Molybdenum <1
Nickel 4.9
Lead <2.1
Selenium <2.5
Zinc 5.1
The symbol "<" indicates the minimum detection limit. The metal was not found at or above the minimum detection limit.

Steve

[Shadetree]

Most of the Dolomite purchased originates from or through Washington. It does not really matter who packages it because they all buy it from the same manufacturers. I currently have over 2200 pounds of it in the back of my truck for work.

Scott